Transmission



O. K. KELLEY Jan. 28, 3953 TRANSMISSION 9 Sheets-Sheet l Original FiledMarch 26, 3.949

o. K. lKELLEY jan. Z3, QS

TRANSMISSION 9 Sheets-Shree?l 2 Original Filed March 26, 1949 o. ik.KELLEY TRANSMISSION 9 Sheets-Shea?l 3 Original Filed March 26, l49

O. K. KELLEY Jan. 25, 21,958

TRANSMISSION 9 Sheets-Sheet 4 Original Filed March 26, 1949 www (INNWimm Q. K. KELLEY TRANSMISSION Jan., 28, 1958 u Sheets-Sheet 5- QrgnalFiled 'March 26, -1949 C. K. KELLEY TRANSMISSION J@ 2s, 1951s OriginalFiled March 2`6, 1949 m.. e n v. w G

im. 28, i958 o. K. KELILEY 22w95 TRANSMISSION Original Filed March 26,1949 9 Sheets-Sheet 8 :inventor O. K. KELLEY Jan. 28, 1958 TRANSMISSION9 Sheets-Sheet 9 Original Filed March 26, 1949 United States Patent OrRaNsn/nssIoN Oliver K. Kelley, Bloomeld Hills, Mich., .assigner toGeneral Motors Corporation, Detroit, Mich., a corporation ot DelawareContinuation of application Serial No. 83,618, March 26, 1949. Thisapplication Uctober 19, 1955, Serial No. 541,653

3S Claims. (Cl. 74-64-5) This application is a continuation of myapplication, Serial Number 83,618, filed March 26, 1949, now abandoned.

The present invention relates to a combination of fluid torque converterand gear drive mechanism which provides plural ranges of torqueconversion through a hydraulic torque converter, and provides foruninterrupted changing between ranges of the driving torque of thecombined drive mechanism, by fluid pressure actuator means, operativeupon ratio-determining brake and clutch elements.

It relates to arrangements of fluid turbine torque converters withgearing, wherein the iiuid torque converters are of a type which has aneffective operation cycle ranging from maximum torque multiplication tosubstantial oneto-one drive; and to the combination of such torqueconverters with change speed gearing arranged to be changed under torqueby the fluid pressure actuation and control means.

lt pertains further to special fluid pressure regulating devices whichcoordinate pressure controlling forces with ratio selection controls forsuch drive assemblies, which devices not only provide variable pressuretiming of the shift intervals; but also provide regulating means for thedriving torque in plural ratios, which regulating means respond tovariable pressure Vregulation during inter-ratio transitions.

The invention further pertains to the utilization of plural pump lluidpressure supply means variably controlled for providing thetorque-sustaining forces for the gear change mechanism, in which thesupply pressure becomes automatically and variably eiective for all ofthe required drive and control operations of the assembly under alldrive conditions.

The invention pertains to drive controls for such drive assemblies inwhich there is a single ratio control for the operator, capable ofestablishing any desired drive ratio by simple motion from one stationor position to another, all other controls being wholly automatic withrespect to the ratio actuating and holding pressures.

A primary object of the invention is to provide a fluid torque converterwith a combined gear train having a full range of uninterrupted torqueoutput under all driving ratios, and including full torque and maximumperformance operation in the ranges determined by the change of ratiosof the gear assembly for all of the driving ranges above an initialpredetermined speed and torque. A further object of the invention is toprovide a gear train serially driven by the torque converter havingfluid pressure actuated ratio changing mechanism effective for directforward drive, low ratio range drive and for reverse drive; in which theuid pressure actuation 'ice mechanisms are supplied by constantlyregulated line pressure, automatically maintained, variably applied andcontrolled by a single manual valve.

An additional object is to provide a fluid pressure supply system forthe aforesaid constructions which maintains a positive pressure in theworking space of the torque converter, maintains through the same, asteady flow of Huid which is traversed through a cooler device and whichutilizes the differential pressures of that space to voperate modulatormechanism controlling the said regulated pressure.

It is an object of the invention to utilize pressure control valvingwhich automatically maintains the flow of fluid to the torque converterWorking space, while simultaneously maintaining a controlled variableline pressure for the operation of the fluid pressure ratio actuatingsystemi. In this connection it is a further object to control themagnitude of the ratio actuation and holding pressure by a change ofselected speed ratio, such that the pressure performing a tluid pressureactuation operation is varied in vproportion to the degree of torquemultiplication required.

Another object Ais the provision of special valve means and mechanismwhihshall be responsive to the variations in the ,power andloadconditions during upshift and downshift ratio changes, and whichintroduce a dynamometric characteristic for providing smooth torqueshifts under all change of drive operations.

An additional object i s to provide a rselective oil liow control,thermally operated, capable of producing an laccelerated cooler ow of'fluid from the torque converter during increased torque intervals,Vcorrelated with delivery of -cooled oil to lubrication passages.

Another object is to provide an overcontrol upon the regulated linepressure mechanism and modulator devices which shall respond to sudden`demands for accentuated engine-brakingand full 4torque operation.

In generally known constructions in which uid drive is obtained bybladed turbine 4devices known as torque kconverters, it has not beenknownto place suchconverters between the source of driving power and a4speed change gearing unit which aiordedfull torque shift underl alldrive conditions. In the case of gear units shown in prior art arrangedin series with a primary drive torque converter, it has been generallynecessary toqunload the drive in some manner for the change of driveratio, this process resulting in dwell interval losses, as well as jerkytransitions tendingto shock the drive mechanism and cause discomfort tothe driver and passengers. The presentrinvention avoids thesedifhculties by utilizing a special form of torque converter which iscapable of delivering full' torque acceleration from maximum reductionto substantial l-to-l drive without interruption, and second, byutilizing aspecial form of a regulated gearratio shift actuator systemwhich variably lcontrols the transfer of torque from one drive ratio tothe other by :devices which measure no t only the degree Vof existingtorque and power llow, -but also which establish a predetermined amountof torque overlap during the shift intervals, The result of thiscombination is a drive assembly having units which inherently providefull ranges of torque multiplication with full capability of changebetween said ranges without surges of unbalanced torque which couldappear as shock accelerations or decelerations. As Vdescribed below, thecombinations stated above permit the car driver to accelerate from standstill to full speed in either ,of two forward drive gear ranges, or toinitiate acceleration in one range. and shift to the other Y for lowforward drive.

during the acceleration interval or at any other time. In practice, withpresent high-compression motor car engines, this combination enables thecar driver to obtain maximum performance whenever needed, without thenecessity of performing any extra manual operation other than movementof a ratio control handle from one station or position to another. Forordinary driving use this stated ratio range shiftof the control handlehas been found unnecessary, and the lower rangeofspeed ratio afforded,is Vrequired to be used only` for emergen-cy low range drive purposes,making available the ultimate acceleration performance of the driveequipped with this invention, at all times. The control handle alsoserves as a parking brake controller, while unloading the pressuresystem.

The gear train used in the combination herein is believed to possesselements of novelty although the general form is thought to be old. Thegear train is equipped with a driving sun gear and a reaction sun gearwhich are clutch-coupled for l-to-l drive of the output connectedcarrier.` The driving sun gear meshes with a long planet gear which ismeshed with a short planet gear, the latter meshing with the reactionsun gear. An annulus gear meshing with the short 'planet is braked forestablishing reverse gear drive, while the reaction sun gear is brakedThis train is supported against rockingcouples yby close tting of themembers at inward radial points, with proper bearings. The compact gearkarrangement enables the clutch mechanism to be compartmented adjacentthe gearing and supported by web extensions of the casing through whichthe controlling fluid pressure is fed directly from an adjacent valveassembly. As will be understood further the gear and clutch assembly iscompartmented separately from the fluid torque converter, with supplypump passages connected through a casing web section between theconverter and gear unit compartments. The supply sump is separatelycompartmented. The construction shown permits unusualrigidity and exactalignment, while affording space for converter uid passages and thecontrols. A second extension of the casing assembly at the rear of thegear unit houses a pump which may supply the fluid pressure system underall driving conditions except for primary drive.

The extensions of the casing between the converter and gear unitcompartments provides reaction support for one-way devices which preventbackward rotation of a plurality of stators of the torque converter, andwhich connect plural impellers of the converter.

The torque converter assembly shown has some novel features. It consistsof ve bladed elements located so that the impeller is in the outflowzone of the working space, the driven turbine rotor is in the inow zone,the two rotatable reaction rotors are in the inner radial zone bridginginflow with outflow, and the tifthbladed element 1s an auxiliaryimpeller located in the radially inward portion of the outflow zoneadjacent the second of the two reaction rotors. The reaction rotors areprevented from backward rotation by one-way brake devices, and anauxiliary impeller is connected by a oneway clutch to the main impellerso that under high torque and high toroidal flow velocity in theconverter working space, the auxiliary impeller may respond to thevelocity effect and run forwardly faster than the main impeller. Thisconverter provides uninterrupted drive from initial maximum torquemultiplication to approximate l-to-l ratlobetween converter input andoutput, which in combrnatlon with the change gear unit equipped withfulltorque shift actuation and variable torque capacity controlfacilities, gives a wholly new drive acceleration fromv standstill to1to1 drive, in which the range of ratio may he changed at any time, bothranges providing full performance output where demanded by the operator.There are no dwells whatever in this shift arrangement.

There are herern, in the described invention, special control featuresparticularly adapted to the drive mechanism disclosed, these controlsdriving from variable pressures regulated by the drive conditions to setup accurately determined actuating and holding pressures for theratio-establishing members of the transmission, and these controls arealso made operative for scalar Pressure values by the operator settingsof the ratio selector mechanism, which mechanism may be readily movedamong the drive positions, while the variable pressure controlsautomatically operate to provide suicient torque capacity for all theneeds of the drive mechanism, and without shock, and permit one toobtain special enginebraking action for emergency operation.

Further advantages, novelties and new and usefulresults appear in thefollowing description and attached drawings which represent one exampleof theinvention herewith, in which: Y

Figure l is a vertical elevation in section of a vehicle drive assemblyembodying the invention showing a iluid torque converter, gear train,oil pumping and lubrication system and an arrangement of compartmentingfor` the separate units.

Figure 2 is a part section taken at 2 2 of Fig. 1 to show the reversedrive actuator mechanism; and Figure 3 is a similar section at 3 3 ofFigure 1 to show the low range drive actuator mechanism, andV portionsof a pressure modulation device which operates automatically forproviding variable regulated pressures for actuating the differentratios of drive afforded by the converter and gear units of Figure l.'

Figures 4 and 5 are sectional views of the parts of a manual controllinkage connecting valve operating and parking brake mechanism with theprimary manual controls.

Figure 6 is a sectional view of a valve arrangement, one of the valvesof which is shown in cooperation with the modulator device of Figure 3,the other valve being operated by the linkage of VFigures 4 and 5.

Figures 7 to ll are composite diagrams embodying control parts, unitsand Velements of the foregoing Figures l to 6, Figure 7 showing theoperating conditions for neutral; Figure 8 for low range; Figure 9 fordirect;

Figure 10 for reverse, and Figure 11 for parking.

Figure l2 is a view of the external control parts connected to andoperating the construction of Figures 4 and 5 as adjoining the lowerportion of the steering column of a vehicle, and Figure 13 is a View inpart section of the external hand controls located at the upper end ofthe steering column cooperating with the structure of Figure l2.

Figure 14 is a part-sectional view of a pressure modulator device whichmay be used as a replacement for the modulator mechanism of the showingof Figures 3 to 1l, representingsome economies in numbers of parts,simplicity of connections, and a dierent approach to solving the problemof obtaining extra torque capacity in emergencyratio drive. Figure 15 isa modified control'valve for the Figure 14 structure, shown with apart-section of a valve body, and Figure 16 is a modification of anaccummulator valve arrangement to that shown at the right of Figure 14.

Figure l is a Vertical section taken through the transmission assemblyof the invention, to show the relative positions of the parts and units.The vehicle engine is located at the left, and constantly drives theunit next adjacent, which is a uid torque converter, arranged to drivethe assembly output shaft 60 through a two-speed and -reverse planetarygear unit. s

The forward portion of the assembly is contained within the housing C,rand the rear portion within the second housing-100 continuous with theiirst, the converter compartment section being denoted by 100e, the gearsection lThe engine crankshaft 1 has atiange bolted to a plate 2 whichis attached at section 3, to a drum 4 acting as width 'between theradial portions of the carrier 28 and gear 35 is meshed with the planets31 and is attached to aradial web 36 of drum 37, splined internally toaccommodate'clntch plates 40. The left portion of the drum 37 at itsinward portionY extends axially to the right, and is tted with the keyedflange 41 acting as a retainer for spring 48. The internal clutch platehub 43 is splined to shaft 11, and is externally splined to accommodateplates 45,'which mate with clutch plates 4t). A clutch presser piston 44is mounted to slide inside the drum 37 within the seal members 46 and47, and is normally held to the left by the clutch release spring 48,which bears against the ange 41. As will be understood further uidpressure is admitted by passage 184 at the left to cylinder 49 betweenthe radial wall Vof the drum 37 and presser or piston member 44 tocompress the stack of clutch plates 40-45 for obtaining a locking couplebetween the sun gears 27 and 35, which establishes direct drive betweenshafts 11 and 60,'thru the gearing. A further clutch cylinderconstruction is shown in Fig. 9, in detail.

The drum 37 is surrounded by a brake member 50 so that it may be heldagainst rotation and cause the sun gear 35 to stand still; requiring theplanet pinions 31 to roll around the sun gear 35. As will be understood,when band brake 50 is actuated, the shaft 11 drives the shaft 60 `at lowgear ratio.

Surrounding the planet gears 31 is a meshing annulus gear 38 attached todrum 51 supported -on bearings 51a on a cylindrical portion of carrier38. The annulus gear 38 and drum 51 are Vsurrounded by a band brake 55which is actuable for stopping the drum and annulus 38 to establishreverse gear drive between the shafts 11 and 60.

The rear portion of the gear casing 100 supports the shaft 60 by bearing51b. The shaft 60 is splined for small speedometer gear 61 and foruniversal joint coupling sleeve 61a.

As described t-o this point, the engine drives the torque converterassembly, which in turn drives the gear unit G, which determines one ofthree driving conditions for shaft 60; namely, low range, high range, orreverse gear drive.

In Figure 2 the casing 100 is broken away and the partsections ofreverse band 55 and drum 51 of annulus gear 38 of Figure 1 are shown.

The band apply end 52 is notched to receive wedgeshaped apply tang 53 ofapply link 54 supporting pivot' 56, and has the projecting ear 57apertured for alignment bolt 58 and forming a seat for the adjacent endof releasing spring 59.

The band anchor end 62 is similarly notched to receive anchor strutpiece 63 pivoted in a notch of the adjustable anchor 64, and is piercedto accommodate bolt 58, and formed to receive seating spring 59.

The casing 100 is recessed to form a cylinder 65 for piston 66 andapertured to guide the piston rod 67 slotted at 68 to register with arm79 pivoted on shaft 56. The upper end of the arm 70 is formed to engagestrut 63 and pinch the band 55 on the drum 51 when the piston 66 isurged by pressure fed to passage 170 to compress piston return spring71, and rock lever 70 counterclockwise.

Pressure in cylinder 65 loads band 55 and release of the pressurepermits spring 59 to release the band 55. The external casing section 73forms the head for the cylinder 65. The piston 66 has limited slidingmotion on rod 67 compressing the spring 71a until the end stop 72 isencountered. This applies force gradually to the band 55 during theloading interval.

Figure 3 shows the casing 109 broken away and the part-sections of lowgear band 50 and drum 37 of sun gear 35 of Fig. l. The band 50terminates in end portions 74 and 76, the end 74 being notched toreceive anchorstrut 75 supported by the adjustable anchor 77 secured inthe casing, and having ear 78 similarly used as that of theAv Figure 2construction The band end 76 is notched for apply strut 80 which 'titsinto the notch of rod 83 of'4 piston 84 in the servo cylinder 85 formedin the casing.

The spring 81 spreads the band ends 78 and 79 for brake release wheneverthe piston, under the inuence of piston` return spring 86, is fully tothe right as Fig. 3 is viewed.

The small spring 87 is threaded into the strut 8i) to hold the strut onthe piston rod and `establish a given piston travel before the end 76 ofthe band 50 is moved for brake actuation. The casing portion 180 formsthe head for cylinder 85. The passage 187 delivers brake apply oil tothe cylinder on the right of piston 84 and the j passage 151 deliversbrake release oil to the left of the piston as Fig. 3 is viewed.

`The arm 135 bears on the regulator valve stemv 125 (Figs. 6, 7) as willbe explained and is pressed upon byV p' transfer pin 137, diaphragm 140,transfer pin 145, diaphragm 146 and by spring 147 retained 'by cap 183,the

for-ce of the spring 147 beingvaried by engine vacuum connected topassage 148. The structures of Figures 4 and 5 are to show the mechanismfor operating the parking brake acting on the toothedmember 29 of Figure1, which rotates with thc output shaft 60.

The pawl member 9i] is mounted for limitedV rotation, its shaft 91 beingsupported in casing 100, and its teeth 92 are formed to intersect theteeth 93 of carrier member 29 when the pawl is rotated counterclockwise.The pawl ,.retracting spring 94 has one end bearing against thevadjacent casing wall and the other end is hooked to apply a clockwiseforce to the pawl 90.

The shaft 89 is fitted to support arm 95 for rotation, j

the swinging end of the arm having a rounded channel formation,presenting outer guide faces with a roller 169 pinned to act as a pawlcontact member t-o move pawl 90 into locking position. The adjacent edgeof the pawl 90 is cut into a series of scalloped portions 96 from right.

toward the left, the final or terminal form of the cut at the left beingthat of a shallow cam 96a. The length of the arm from the center of theshaft 89 with respect to the permissible motion and thickness of thepawl 90 is such that when the arm 95 is in its extreme counterclockwiseposition, the teeth 92 of pawl 90 are positively seated in teeth 93.

The shaft 89 rotates in concordance with lthe movement of the manualvalve 131) of Figure `6. The station positions in counterclockwisesequence are reverse, low,

high, neutral and parking brake, denoted bythe rock the arm 95counterclockwise in Figure 5 for initial i engagement of the pawl 90with the carrier ange teeth 93. If the vehicle is still in motion, therounded tooth ends tend to reject mesh of the pawl teeth at 92, 93 andthe spring 97 yields. During this action, the control force applied bythe external control opposes that of the pawl spring 94. The left endkof shaft 89 is supported in a portion of a lever 108 which operates thecontrol valve 130 of Figure 6.

Carrier 28 ceases rotation when the vehicle motion isr stopped, thestored energy in spring 97 seating the pawl teeth 92. Once seated, thearm 95 is normal or perpendicular to the pawl cam face 96a so that theange teeth 93 cannot force the pawl teeth 92 out of mesh.

The arm 95 with roller 109, and the pawl cam face 96a permits easydisengagement of the pawl 90 even if `the .vehicle is parked on a grade,because the holding force vehicle torque, and the rounded teeththereupon may force the pawl out of engagement, aided by springv 94.

The scallop portions 96 on the edge vof the pawl 90 'adjacent the end ofthe arm 95 serve as station feel poppets for positioning of valve 130 ofFigure 6, as will be understood further below. The roller 109 by reasonof its small diameter is capable of release action with very littleforce applied thru spring 97.

Figure 6 shows a sectional view of the pressure regulation modulatorvalve mechanism shown in Figure 3 utilized to determine withconsiderable accuracy the instantaneous value of the controlled pressureprovided by the regulator valve 125.

The casing portion 100 is formed with the various passages shown, and isequipped with bore 124 for regulator valve 125, and with bore 126 forthe manual selector valve 130.

The bore 124 is ported in order from the right at 127, 128, 129, 131,132 and 133. The valve 125 has bosses a, b, c and d as shown, and a stemportion e protruding from the casing, and spring 134 tending to hold thevalve 125 inward in the bore 124, the right portion of the spring 134seating in a recess of the modulator casing 181.

The smaller portion of the stem e is guided axially in an aperture ofcasing 180 and is pressed upon by multiplier arm 135 pivoted at 136 inthe casing portion 180. As shown in Fig. 3 a transfer pin 137 guided ina boss 138 of casing portion 182 bears against the arm 135 and is borneupon by the diaphragm 140 of Fig. 3 clamped between portions 181 and 182of the casing. Fluid pressure passage 141 is open to space 142 to theright of the diaphragm 140, and passage 143 as shown in Fig. 7 is opento space 144 at the left of the diaphragm 140.

A second transfer pin 145 is guided in an aperture of the casing portion181, and is borne upon by a second diaphragm 146 clamped betweenportions 181 and 183 of the casing, and is pressed inward by spring 147recessed in the casing portion 183. Passage 148 is connected to theintake manifold of the engine, so that the force of spring 147 upontransfer pin 145 is varied by the vacuum conditions of the manifold asdetermined by the engine speed and throttle opening.

It will be seen further that there are five forces operating upon thesetting of the regulator valve 125, that of the spring 134, the forceson either side of diaphragm 146 derived from the converter inlet andexit pressures, the force of spring 147 and the varying force of theengine vacuum on the action of spring 147.

There is still another force exerted on valve 125, derived from theregulated main line pressure. The pumps feed into main line 162 and intospace 133 by passage 123 and this pressure is effective on the face ofboss d, tending to move the valve against spring 134.

The primary regulation action is for the outlet or regulated pressure ofvalve 125 to tend to spill excess pump pressure past the left edge ofboss b as seen in Fig. 6 back thru relief port 128, occasioned by therise of pressure below boss d in space 133.

The tendency is for a diminished delivered pressure to shut off reliefleakage at port 128 by there not being sucient pressure beneath boss dto overcome the force of spring 134, whereas a rise of deliveredpressure to a value greater than determined by the calibration of spring134 will tend to open the relief at port 128 wider. There is anequilibrium pressure condition wherein the delivered pressure forcebelow boss d exactly balances the calibrated spring force. Thisdescription at this point has covered the self-regulation of valve 125,but not the ymodulation effects applied by the engine Vacuum and theconverter inlet and exit pressures affecting the action of the diaphragm140.

The overall eect of the vacuum-responsive portion of the modulatordevice of Figures 6, 7 to 1l and 14 is to provide a constantly availablepressure `regulation for valve 125 under all driving conditions, so thatwith high 1 0 torque demand as called -for .by the vehicle driver inladvancing the engine throttle, the. force of modulator spring 147becomes instantly available for increasing the leading of stem e ofvalve 125, which requires a greater force to move the stem to ventingposition at port 128, and thereby raises the effective regulatedpressure available in main line passage 162 and the servo actuatorpassages connected to it by valve 130.

At light or idling throttle, the degree of engine vacuum effective inline 148 to move diaphragm 146 is relatively high, and the force ofspring 147 is diminished or eliminated. This results in valve 125providing a regulated pressure range of minimum or near minimum value,as determined by the other forces acting on the valve 125.

The response of the diaphragm andy spring 147 is not only conditioned bythe engine throttle variation, but also by changes in the overall loadof the vehicle such as induced by encountering up-grades, and islikewise conditioned to some extent by the encountering of a downgrade,which by lightening the load on the engine, would cause the degree ofvacuum to rise and transmit a signal which would diminish the effectiveline pressure. Under this condition, it is therefore desirable tointercept this action or render it less effective to drop the linepressure to minimum, especially in the higher ranges of vehiclespeeds-since it is necessary to maintain a useful margin 0f linepressure, so that if the operator desires to change to low'range, forincreased engine braking-some other control force is then utilized toapply a secondary modulation effect, and maintain a higher level ofminimum line pressure increasing with speed.

Therefore the converter inlet and exit pressures are made effective thruthe pressure effect on the diaphragm 140, as will be understood byreference to the specification description of the effect of theconverter inlet and outlet pressures on the diaphragm 140 of Figures 7to 1l.

As will be understood further in connection with the description ofFigures 14 to 16, wherein the converter modulation pressures arereplaced by line pressure when in low gear, only the diaphragm 146 isneeded, the operating parts tlinking the diaphragm 146 with the lever135 assuming other forms and characteristics, described below in detail.

The regulator port 127 is connected to two passages 151 and 152, thepassage 151 leading to the brake release space of the low band servomechanism as shown in Figure 3, whereas the passage 152 is open to thecylinder 49 of the direct drive clutch servo mechanism of Figure l.

The boss a of valve is of larger diameter than boss b, hence as will beunderstood further, a pressure in passages 151 or 152 would tend to actdiiferentially upon the exposed adjacent cylindrical areas of thesebosses, having a net effect of lifting the vaflve 125 against the spring134, to lower the regulated pressure.

Reference is now made both to Figs. 6 and 7. The port 128 is open to thesuction of both pumps P and Q, in passages 153 and 154, and to the sumppassage 155.

The port 129 is open directly to front pump delivery passage 156, and tomain line 162 through port 157 of double-check valve 168.

The port 131 connects to feed passage 161 leading the converter workingspace.

The port 132 is open to the main line 162 leading port 172 of valve 130.

Bleed orifice passage 123 connects the inner end of bore 124 to thepassage 162.

The valve body bored at 126 vfor manual valve 130, which is pivotallyconnected to arm 168 of control shaft 89.

Port 171 connects to passage 170 leading to cylinder 65 of the reverseband servo mechanism.

Port 172 is open to main line 162 to receive regulated pressure fromregulator valve 125.

Port 173 is connected to passage 187 leading directly to the apply sideof the low band piston 84.

Port 174 yis open to passage 184 leading to the direct drive clutchcylinder 49, thru orice 197 shown in Figure 9.5

Port 175' is open to exhaust.

Port 176 is connected to passage 190.

Port 177 is open to converter inlet passage 168.

The port'178 is open to passage 191 leading to passage 143 of themodulator mechanism of Figure 3.

Port 179 is open to converter exit passage 165 and port 167 is a ventfor conduit 190. The spring 160 has two arms 160a` and 160b each formingan independent normally closed check valve for the front pump P and rearpump Q respectively. Either-pump alone, or both pumps together can openone or both check valves, as the case may be to supply-oil to main line162. Whenever front pump pressure exceeds rear pump pressure valve 160bis closed, and the front pump supplies theentire require-1` ments of thesystem. Conversely, whenever the rear pump pressure is greater that pumpsupplies the system and the front pump check valve 160:1 is closed.

A pressure relief valve 192 is exposed to the pressure in port 172 andconsists of an exhaust-connected sleeve 193 containing a loading spring194 for check ball 195 seated at 196 against the pressure in port 172. f

The Figures 7 to 11 show the elements of the luid pressure system forthe operation of the structures of Figures 1 to 6.

With the control for ratio selector Valve 130 set for neutral N, thevalve is stationed as in Fig. 7. Boss f vents reverse line 170 at theopen end of bore 126, preventing servo iluid from reaching line 170 byblocking the input port 172, while overpressure valve 195 remainsoperative. Ports 173, clutch line 184 and low brake line 187 are ventedat port 175.

Land j opens port 167 to vent passage 190 which is in turn connected topassage 141 of the space 142 above diaphragm 140 of the modulatormechanism at the top of the drawing. Port 177 is blocked by boss h ofvalve 130, therefore there is no connection for passage 168 connected toconverter input 161. Port 178 is connected to line 191 leading topassage 143 and the space 144 below modulator diaphragm 140, and boss ipermits connection between this line and passage 165 connected to theconverter outow system.

Pump P is furnishing oil to line 156, but since the vehicle is standingstill, pump Q is idle and not delivering pressure to line 159, hencedouble-check valve 160 closes port 153, while pressure in. port 129,passages 156 opens 160 at port 157 to deliver oil to passage 162, thepressure of which thru the connection of passage 123 with space 133,tends to lift the valve against spring 134 toward the regulation pointwhere the lower edge of boss b will rise to vent the line at relief port128.

Pressure between the bosses c and d of valve 125 does not directlyaffect the regulation action of 125 since the bosses c and d are ofequal areas; and the port 131 delivers pressure to converter feedpassage 161; and the low from the converter thru passage 165 passingthru orifice 201 and line 202 to the thermal valve space 205 to thecooler 211 and by the passage 212 to the lubrication system.

Since the passage 190 is blocked at 177 from the converterfeed-connected passage 168, there is no force available above diaphragm140 to apply pressure on modulator arm 135 for increasing the pressurein 156, 162 th-ru the variable load action of 135 upon the stern e ofvalve 125;`

and further, theconverter outow pressure in passage 165 appears in ports179, 178, line 191 and passage 143 tending to lift the diaphragm 140.

If the engine is idling, the high vacuum lets diaphragm 146` opposespring 147, but the engine may be raced, and cause a diminishing of theeffective vacuum, so that spring 147 may press diaphragm 146 downwardagainst the' upward force createdby the converter outflow pressure inthe space under diaphragm 140. I

With the control for valve operated to shift to low speed ratio, thevalve 130 is moved upward to the Figure 8 position. Boss f blocksreverse port 171 and regulated pressure from main line 162 is admittedby ports "172, 173 to the apply end of brake cylinder 85, thru passage187. Boss g is stationed to exhaust the high clutch line 184 at 175, andboss h rises to permit converter input pressure from 168 to pass thruports 177, 176 to and 143 to urge diaphragm 146 upward.

Brake 50 being applied by piston 84 on drum 37, drive proceeds in lowgear. l The regulation eiect of the converter input and output ipressures upon valve 125 thru the agency of the modi ulator mechanism isdescribed further in detail below.

During drive in low, pump Q being driven, now de-` livers pressure topassage 159, opening valve -at port -158 `to add its pressure to thateiective in passage 162 and its connected ports and passages.

blade 160a of 160 is seated at 157 by the pressure in lthe passage 162and between the blades, prevents backflow into passage 156. Thekpressure in space 133 to lift valve 125 to connect exhaust port'128 tofeed port 129 from pump outlet passage 156. When this occurs, the frontpump P can then idle, being subject only to whatever light circulationload or resistance appears in 'the relief passages 153, 155 and 154.

Feed to the converter Working space is thru orice port 131 from the bore124 of valve 125,`to passages 161 and 168 and the radial space betweenimpellers 6 and 5. The fluid from the Working space is circulated inwardradiallyvbetween turbine O and reaction wheel R-l to passage 165, thepressure reacting from passage upon the inner face of valve 200 wheneverthe outlet pressure is greater than the inlet pressure, to open thelvalve 200 and connect momentarily both the inlet and exit converterpressure-connected spaces. The outflow from the Iconverter passes thruorifice 201 in passage 202 leading to the thermostat valve 203 and tothe cooler feed line 210. The pressure diierential valve 200 isnotspring loaded, but only responds to any rise of converter exit pressureabove the instantinlet pressure value, to equalize these pressures bycirculating tluid from exit direct to inlet. This guarantees that theconverter cannot ever generate a positive modulator pressure, that is,exert on the modulator a higher outlet pressure than inlet pressure. n

The converter exit pressure appears in passage 165 connected to port 179of valve 130, and on the underface of modulator diaphragm 140,thru theconnection 191.

The converter inlet pressure appears on the upper face of diaphragm 1.40thru the connection 190.

The control requirements for the proper operation of the regulator valveby the converter pressure differential, inlet to exit, are such that anegative pressure characteristic is desiredv-,which is to say that theinlet shall always be greater than the exit pressure-guaranteedby theoperation of Ydilerential valve 200. y

Translatingthis to the desired action of the diaphragm 140 Vof themodulator mechanism for the regulator valve 125, it is desirable thatthe Vpressure to the right of the diaphragm be always rgreater than thatto the left, as viewed in Figure 3, when operating in low.

During drive in low, it is desirable to maintain a substantial holdingpressure on the low band 50. Whenever lthe front pump is unloadedpressure in main line 162 is controlled by the amount of opening of port129 by the lower edge of boss c of valve 125. For this, the stem e ofvalve 125 is variably urged downward against the upward pressure belowthe valve in space 133, and the arm 135 exerts a variable force on steme in accordance with 75the'tota1 eect of spring 147, vacuum abovediaphragm. x

When the pres sure of Q exceeds the pressure of P the right hand 146,and the converter differential inlet and exit pressures on either sideof diaphragm 140.

The detail of the modulator effect is given below in connection with theoverall statement of operation.

ln Figures 7 and 8 in the lower right corner a brokenaway section of thecasing space at the right of the gear train support is shown, withlubrication pipe 212 connected to space 240. The shaft 6i) is piercedand drilled for lubrication llow from pocket 240 to the transmissionbearings and gears. The centrally drilled passage 241 in shaft 60 hasradial inlet 242 and axial outlet 243. Referring to Figure l, the shaft11 is hollow, it connects with passage 241 and it connects to radialoutlets 244 and 245, the outlet 245 feeding to the space at the left ofsun gear 27 and the outlet 244 opening into the shaft space insidecollar 23 for ow to the web space of clutch hub 43. The bearings 51a and51b are directly lubricated from pocket 240, which is under a constantpressure about 4 pounds above atmospheric in practice.

Figure 9 shows the selector valve 130 positioned for drive in direct,delivering from feed port 172 to both the low gear port 173 and theclutch feed port 174. Boss f is drawn down to connect reverse port 171to end exhaust; bosses g and h isolate exhaust port 175; boss h blocksport 176 so that converter inlet pressure does not pass thru the loopportion of 190; bosses h and i connect ports 177, 178 to admit converterinlet pressure from passage 168 to passage 191 leading to the undersideof modulator diaphragm 140; and bosses z' and j connect ports 179 and167 admitting converter exit pressure from passage 165 to passage 190leading to the upper space 142 above diaphragm 140.

The invention herewith embodies a special feature which in combinationwith the other features described, provides a useful result worthy ofspecial attention. Reference has been made to the connection from theclutch cylinder 49, passage 152 to port 127 of the regulator valve 125,and passage 151 leading to the release side of low range piston 84 incylinder 85.

It should be rst observed that there is no pressure fed to thesepassages and pressure spaces except when the manual valve 130 is in thedirect drive position of Figure 9 to feed regulated pressure to the port174, line 184, orifice 197 and cylinder 49. When this manual valvesetting is in effect, the line pressure is also fed to the passage 187which in the low range setting of Figure 8 feeds pressure to thebrake-actuation side of piston S4 of the low range cylinder 85.

In the direct drive control setting of Figure 9, it will be noted lthatthe piston 84 is subjected to pressure on one side delivered by line187, and on the other side delivered by line 151. Since these pressurevalues are -both equal, the piston 84 is not moved by either pressureforce, but is under the force of spring 86 which holds the piston 84 soas to permit 81 in Fig. 3 to hold the low range brake 50 released.

Consequently if the clutch cylinder 49 is drained by movement of valve130 from direct drive to low position, the rate of release of pressurefrom the release end of the cylinder 85 is controlled by the orifice197, and this controls the corresponding movement of piston 84 to setthe low brake. It is noted that the brake-actuation pressure is alreadyin the actuator end, by the connection of passage 187 to main line atport 172 of valve 134). This change-over may be visualized as one inwhich the required loading force for the brake is held in equilibrium bythe existence of clutch loading pressure, and when the equilibrium isupset by the removal of the clutch loading pressure, the brake actuatorforce is already waiting to act, as rapidly as permitted by theregulated release of the clutch pressure from the cylinder 49.

Now, in Figure 8 for describing the control settings for drive in lowrange, it is lseen that the brake release spring 86 is held ott bypressure in cylinder 35 fed thru line 187 14 from port 173 of valve 130,and 'that clutch feed port 174 is open to exhaust.

When the valve 130 is then shifted to the direct setting of Fig. 9, thepressure which had been exerted to hold band 50 applied, is notexhausted, but its effect on piston 34 is diminished by the rise ofclutch pressure as further exerted in 151 passages 152 and thru port127, and fed to the release end of cylinder 85, the rise of the brakerelease pressure continuing until the luid pressures on either side ofthe piston 84 are again equalized, by which time the brake 50 is fullyreleased.

This peculiar system and principle of obtaining alternate direct clutchand low range brake application enables a very close overlap control tobe exercised over the change speed interval for both upshift anddownshift, and prevents any possible run-away olligling or unloadedtransmission members. Directing attention to the status of the sun gear35 and drum 37, these connected elements are never, during the operatingcycle, free of restraint or of control, since the oil body underpressure in the connecting passages between the release end of cylinder86 and cylinder 49 serves as a definite linkin the clutch actuator andbrake release forces which assures complete coordination during theshift in either direction, and makes possible accurate timing of theshift.

Other noteworthy response actions occur during these upshift anddownshift intervals, such as the timing effects derived from the phasingof the directional wrap of the low range band 56, and the resultingdropping of the regulated pressure in space 162 by the existence ofdifferential forces on valve when there is pressure in cylinder 49, line152 and port 127. These response actions are further explained herein indetail.

As noted preceding, the boss a of valve 125 is of slightly largerdiameter than boss b, so that the existence of a pressure in thepassages 151 and 152 in port 127 would tend to decrease line pressure byurging the valve 125 against the spring 134 whenever there is pressurein the clutch cylinder 49.

When the valve 1311 is moved from the Figure 9 po sition to that ofFigure 8, for shift to low range, boss g moves upward to expose theclutch feed port 174 to exhaust at 175, but leaving the low gear port173 still connected to 172 for actuating piston 84 to load band 50 ondrum 37.

The self-regulating pressure effect .occurring in the clutch-releasingand brake-applying interval is to be ex amined carefully at this point.if the valve 125 as inlluenced by the modulator mechanism hasestablished or is establishing a relatively high pressure in the mainline 162, this pressure value will appear in the clutch cylinder 49prior to the downshift movement of the control lever 291? to the lowrange position, and the exposure of the clutch port 174 will initiate apressure drop in the feed passage 134 ahead of the orice 197. Thepressure in 49 is the same as in passage 152, port 127, passage 151 andin the pressure release space of brake cylinder 85. The tendency of theregulator valve 125 is therefore to oppose spring 134 and thus maintainin the main line a lower pressure than would be maintained with theclutch chamber 49 vented.

A tendency is therefore established for widening the aperture betweenthe lower lip of boss b and the lower edge of port 128, and relieve theregulated pressure, creating a pressure drop reected in passage 162 andthe connected passages. Under these circumtances, the timing of thetransition to full brake application by piston 84 is accelerated, whichreduces the potential slip of the band 50, prior to full stopping of thedrum 37.

As shown in Figs. l, 9, a feature of the clutch control system isprovided by a small blade valve 39 pinned to the drum 3'7, consisting ofa self-spring piece normally tending to seal the aperture 26 of thecylinder space 49. The piston member 44 is pressed to the left by theclutch :mairies spring 48, this action opening valve 39 by applyingthrust l to thrust pin 39', numbered in Fig. 9, but not in Fig. 1. Whenoil under pressure is admitted to cylinder 49 faster than it can ow outthru opening 26 the piston 44 moves to the right, and valve 39 sealsaperture 26 because the force of the spring 39 is greater than the forceof clutch apply pressure on the area of the valve. When the pressure isreleased, the automatic leftward travel of piston 44 opens valve 39, toprovide a quick clutch pressure release, the centrifugal force of thecontained oil body assisting this action at high speeds of drum 37, whenthat force is sufficient to force valve 39 open.

In Figure l which shows the reverse drive conditions, valve 130 is setto deliver regulated pressure from port 172 to port 171 and to passage170 leading to reverse cylinder 65 for actuating piston 66 to apply band55 to drum 51 of annulus gear 38. Boss f sealsthe bore end exhaustpassage; boss g isolates the pressure above it, and connects ports 173and 174 to exhaust at 175; boss lz and boss i are stationed to connectports 176, 177 so that converter inlet pressure is connected to passage190 leading to the upper side 142 of diaphragm 140; bosses i and j areplaced to connect ports 17S, 179 so that converter exit pressure inpassage 165 is available to passage -191 leading to the lower side 144of the diaphragm 140.

The regulator valve 125 is subject only to the positive pressurefurnished by pump P, the pressure delivered to valve 160 filling thespace connected to passage 162 and sealing the port S of passage 159against the robbing elect of pump Q which in reverse, rotates backward.

When pump Q rotates reversely, it tends to apply suction to passage 159and to move uid in opposite flow direction in passage 154.

As will be understood from the description following, of the modulatormechanism and its action on the values of regulated line pressure, thenet regulated pressure for applying the reverse band 55 is augmented soas to provide a high gripping force to. deal adequately with the torquereaction force of drum .51.

In Fig. ll, the pressure regulator valve 125 is not effective, since thevehicle drive control is set for neutral, and the control for valve 130as described in connection with Figs. 4, 5 and 6 has shifted the valveto the limit of downward travel in Fig. ll, or the limit of leftwardtravel in Fig. 6.

Since the vehicle cannot be towed or otherwise moved when pawl 90 locksthe member 29 against rotation, there can be no uid pressure supplied bythe pump Q to passage 159. If the engine be started, and pump Pfurnishes pressure to passage 156, the space 162 is supplied by theright hand blade of check valve 160 and there is pressure to port 172 ofvalve 130, which is relieved by the upper end porting to exhaust.

The passages 165 and 168, connected to the converter working space areprevented from draining by bosses g, h and z' of valve 130, so that whenthe control shifts valve 130 to neutral as shown in Fig. 7, thesepassages are likewise blocked. When the engine starts, pump P thereforedoes not have to lill the whole converter working space capacity, butonly the fraction above the drain-down level sustained by the blockedconnections. It should be noted that boss c of valve 125 blocks drainfrom passage 161 in Fig. ll, and bosses c and d likewise in Fig. 7.

With no pressure to lift valve 125, the spring 134 will shift the valveto the bottom of its stroke as shown in Fig. 6. The spacing at bottompoint in the diagram of Fig. 1l is left for clearer understanding, itbeing assumed that a spacer stud at the valve end may be used to assurethe desired linear blocking action described.

The thermostat valve 203 of Figs. 7 to ll consists of a thermal blade204 pinned at one end in the input space 205 and bent at the other endto force the ball valve 206 olf its seat against the force of spring207. The

inlet pressure feed is from passage 202 to space 205,

and the flow may proceed by passage 208 direct to the 16Y cooler 211,and when the blade 204 has unseated the ball valve 206, the flow maypass thru to passage 212 leading to the lubrication feed main 241, theball'check valve 213 being lifted from its seat by the pressure actingagainst the force of spring 214.

Cooled oil from cooler 211 ows by passage 215 to the space 216 betweenpassage 208 and the seat kof check valve 213.

The blade 204 normally holds valve 206 off its seat so that there isdual ow to cooler inlet passage 210 and flow to passages 208, 212, thecooled oil from passage 215 joining the lubrication ow at the pointabove valve 213. When the ow from the converter working spacey inpassage 202 rises in temperature, the blade 206 bends away until it nolonger can overcome spring 207, and

valve 206 closes olf the direct oW to passages 208 and v 212, forcing,all of the converter outow in passage 202 to pass thru the coolerbeforereaching lubrication feed passage 212.

Reference above, in connection with Figures 7 to l1 has been made to thefact that the passages 161 and 202 connected to converter inlet andexit, are equipped with restrictions or orifices 131 and 201respectively.

The applicant'has found that the pressure values derived from the inletVand exit passages Within the orifices 131 and 201, such as are admittedto the modulator l mechanism by the ports 176 to 179 and 167 of valve130,

vary with respect to the converter operating conditions;

and at or near stall when the circulation velocity of the working spaceoil body is relatively high, the outlet pressure becomes greater thanthe inlet pressure. This condition is not desired for obtaining thecontrol char-v acteristics suitable for the required action of thepresent modulator mechanism, therefore thedilferential-pressureresponsive check valve 200 of Fig. 1 and thediagram figures, will open under the increased outlet pressure and spillthe excess back to the inlet passages. This temporary condition has beencalled the positive pressure phase as distinct from these pressurerelationships whenl developed under further converter operation atlesser torque multiplications.

When the torque ratio of converter of the present invention decreases tosome particular value, the inlet pressure in passages 161 and 168 risesabove the exit pressure value in passage 165, and remains above sameduring the later uid ywheel coupling stage. be termed a negativepressure phase.

It seems advisable to trace thru the `diagram `figures the variousoperative ,phases of the converter pressure i modulator system so thatthe characteristic effects on the regulator valve and its resultantregulated pressure values will be entirely clear.

In Figure 7, for neutral, converter inlet pressure is blocked by boss hof the valve 130, and the exit pressure is connected to the lower sideof the diaphragm 140, i having the net efect of reducing whateverpressure increasing forces the regulator valve 125 may receive otherwisefrom the system. In Figure 8 for low range operation, the inlet pressureis delivered to the upper side of the diaphragm and the exit pressure tothe lower side. In Figure 9 for direct, converter inlet pressure isdirected to the under side of the diaphragm 140 'l In Fig. f l0, forreverse, converter inlet pressure is ydirected to the y and converterexit pressure to the upper side.

sure, the net control pressure effects resulting from the .i arrangementmay be tabulated as given futher below.

Referring the described pressures back to the diaphragm of the modulatormechanism, by the passages 141 and 143, it will be understood that theoperating conditions for valve 125 with respect to the action on it bythe This may f 17 converter pressure regulation elect may be tabulatedin accord with the various selection positions of valve 130.

Converter Space Pressure Regu- Connections lation On Valve Inlet ExitInc. Dim.

Fig. 7, Neutral (Blocked) X X Fig. 8, Low Ran e X X X 0 Fig. 9,Direct-.- X X 0 X Fig. l0, Reverse. X X X 0 (X indicates pressureaction.)

It will be noted that in direct the dominating inlet pressure isswitched to exert a lowering eiect on the regulated pressure whereas inthe other ratio or drive positions it is applied to raise this pressureover a variable scale.

The line pressure, in increasing with throttle opening permitsmaintenance of suicient excess regulated pressure to handle all abnormaltorque demands which otherwise could cause slip of the torque-sustainingelements.

The following representative tabulations cover iield Correspondingly,the available regulated pressures in direct drive will tabulate asfollows:

Speedo., Miles Per Hour Pressures, Lbs.

at Full Throttle The merit of the variable pressure effect, varying withvehicle speed lies in the constant creation of a margin of regulatedpressure over and above need to sustain the drive up to all full torquedemands, such as the pounds pressure at full-throttle shown above.

The manual valve operating lever 88 secured to shaft 89 in Figure 4appears in Figure 12 where it is seen endwise, the end being aperturedto receive the turned end of rod 279 pivoted in short arm 281 formed inthe same piece with the longer lever 280, pivoted on the stud 282mounted on the youter wall of the casing 100. As lever 28@ is swung, thesmall arm 281 thru rod 279 swings lever 88 and rotates shaft 89 to thepositions P, N, 1), L and R, indicated.

The steering column 306 of the vehicle is fitted with bearing bracket283 in which the lower end of selector shaft 285 is pivoted, the shaft285 having an arm 284 secured to it. The arm 284 is pivotally fitted at286 to link member 287, pivoted at 283 in the lower end of lever 286.

Rotation of shaft 285 swings arm 284 to reciprocate link 287 and movethe lever 281) and arm 281 to and among the positions indicated, causingthe shaft 89 to rotate for moving the valve 130 `of Figure 6 and theparking brake device of Figure 5, as described.

As will be understood by further reference to Figure 13, the selectorshaft 285 is rotated by control handle 290 clockwise thru the selectorpositions P-N-D- L-R and oppositely, counterclockwise, resulting instationing lever 280 at P and at R for the limits of shift selectormotion. This correlation will be seen by reference to Figure 5 and thepoppet stationing of arm and roller 109 in the notches 96 of pawl 9i?.

In Figure 13 the steering column 360 will be seen to support a casing291 in which the upper end of shaft 285 is fitted for bearing alignment,this end of shaft 285 being forked to accommodate the sliding action ofthe inner end of selector handle 290 pivoted at 292 to the fork portionof shaft 285. The handle 290 is knobbed at one end, and is equipped withmovable stop finger 293 at the other. The pointer 294 consists of anangular piece attached to the upper end of the shaft 285, projecting ina plane of rotational motion. A signal plate is fastened to the housing291 and is marked for the shift positions, from left to right P-N-D-L-Ras shown, for registry with pointer 294. A position stop plate 296 isattached to the housing 291, and is formed and placed to providesupervisory, permissive control over the handle 290. The shift sequenceherein is more effective in guarding against wrong motion if the allowedplanar rotation of handle 290 and shaft 285 be given a dwell feel forwarning the driver, therefore to halt inadvertent application of thereverse band 55 of Fig. 2, stop 297 of plate 296 prevents direct planarmotion of handle beyond L to the R position, requiring the handle 290 tobe rocked slightly by lifting the knob end, if one would apply the band55 to drum 51 of gear 38 of Fig. l. This lifting action, actually only afew degrees of motion, rocks handle 290 on pivot 292, depressing thefinger 293 so as to clear the stop 297. A second stop 298 formed inpiece 296 is contoured so as to permit passage of the nger 293 butwithout positive blocking of the motion, and only to aiirm the desiredpoppet action likewise derived from the ratcheting action 4of roller 109of arm 95 in Fig. 5 over the scalloped portion of pawl 90. Stop 298 islocated between positions L Spring 301 acts to reset the handle 290 inthe normal planar rotation position for the three shift stations of thehandle between the positive stopped end positions.

The construction of the modulator device of Fig. 14 provides a differentmethod of obtaining increased pressures for high torque needs and forthe regulation of the timing of the shift to and from drive in lowrange.

In Fig. 15 the modified manual valve 130 is shown.

In Fig. 14 the accumulator casing 250 is bored at 251 for plunger 252,and the end chamber 253 is connected to passage 254 which is the passage254 in Fig. l5. Whenever the manual valve is either in L, for low, or Rfor reverse position, accumulator passage 254 is connected to main lineat port 272 thru passage 234.

The plunger 252 moves in bore 251, being urged upward against stop 256by spring 255. Side passage 257 is located above the stop, and leads tothe vacuum modu lator device shown at the left.

The inner portion of chamber 253 is formed into ringshaped seat 258 forplate valve 260, oriced at 261, and the plate Valve 260 is seated bylight spring 262 which may exert a low force of one to three pounds, forexample.

The plate valve 260 is fitted with retainer 263 for spring 259 whichholds a second plate valve 265 upward against a similar ring-shaped seat264 formed on the underside of valve 260. The force of spring 262 may betaken at approximately 50 pounds, and that of spring 255 at 135 pounds.

Oil admitted to passage 254 and chamber 253 from main line passes thruthe orice to open valve 265 against spring 259 and build up pressure onplunger 252 to com- 1-'9 press spring 251 and gradually build uppressure in the modulator.

Themodulator device includes diaphragml 146 held be'- tween cap 183 andsection 181, actedV upon by engine vacuum admitted at port 148 to workagainst the force of spring 147, as before. The casing section 181 isbored to accommodate thrust pins 137 and 145, the pin 145 bearingagainst the lower face of the diaphragm 146 and against the upper end ofpin 137 which protrudes from the casing 181 to operate lever 135, asbefore.

The adjacent ends of the pins 145 and 137 lie in enlarged space 266connected to passage 257 open to the bore 251 above the plunger 252.

The application of a given pressure to modulator passage 254 anddelivered to the space above the plunger 252 is therefore able to liftpin 145 upward against spring 147 while pressing pin 137 downwardagainst lever 135, having the net ettect of causing the regulator valve130,

loaded by lever 135 to createa higher regulated pressure in the mainline 162 and connected servo control passages of the actuator system.

'The elect of the staged accumulator arrangement acting thru themodulator device is to raise the minimum regulated pressure value sothat when the low range band or reverse band is being actuated, therewill be sufficient pressure to hold either band on the drum to preventundesired slip, which would produce unnecessary wear and heating.

When the valve 130 is moved to release the low range band 50 in driveorneutral, but not in reverse, the connection of passage 254 to exhaustport 2 33 vents chamber 226 and permits the heavy spring 255 to moveupwardly, unseat valve 260, so that the spring 147 and the upward forcesacting on lever 135 will again bring the pins 145 and 137 into abutment.

In Fig. l5 the changes in valve 130 to set up a proper initial controlfor the construction of valve body 266 is bored at 126, and the valve130 is provided with bosses f, g, h and z', as shown, comparable withsimilar bosses of valve 130 of Fig. 6.

By comparison with Fig. 6, it will be seen that in Fig. l5, the portsA171, 172, 173, 174 and 175 are the same, providing reverse feed, mainline inlet, low band apply,- clutch apply and exhaust in that order.

The valve 130'- is shown in low range position, the line pressure from162 passage thru ports 172-173 for delivery to passage 187 leading tothe lowrange cylinder 185, to the brake-actuator side of piston 84. Thedirect clutch port 174 is .connected tov exhaust at 175. The reversefeed port 170 is open to exhaust at the end of bore 126.

There are three ports, 4231, 232 and 233 in order to the left of boss hof valve 130', the first, 231 being connected to the main line pressureport 172, by passage 234, the second 232V being connected to passage 254shown in Fig. 14, and the third 233 acting a's exhaust or relief. Asshown in Fig. 15, the modulator port 232 is connected to 231 for causingthe Fig. 14 construction to exercise its pressure raising function.

The stations for valve 130' are indicated at the left, corresponding tothe PN-D-L-R notations of the other iigures. The lever 108 of shaft 89of the preceding figures operates valve 130 similarly to valve 130 ofFigs. 4 and '6;

When the valve 130 is in reverse setting, the Fig. 14 structure is stillfed thru port 232 and passage 254 from passage 234 and port 172. Indirect, the port 231 is -shut ofr by boss hfand 254 is joined to exhaustat 233, which condition also prevails Vin neutral.

If the vehicle approaches the crown of a steep hill, and the operatordesires to utilize full engine braking `in IW range ratio, he need onlyshiftthe handle 290 of Fig. 13 to low rangefL position, and although theengine throttle may be at-retarded or idling position, creating a .high

vacuum whichremoves the e'ect of spring `147, tlie mod-*- ulatorpressure acting between plungers' 14S and' 1-37 in Fig. 14 presses themapart, and loads lever 135 to act on stern e of valve 125,- for raisingthe regulated pressure effective in 162 and the connected passagesleading to the actuation system.

Whenever the vacuum chamber spring 147 is rendered inoperative, theregulated pressure provided by valve tends toward minimum line pressure,since only the force of the spring 134 and the pressure acting on theend of the valve boss d are active, When in direct,I this minimum valuemay approximate 40 p. s. i., and in low range would be about 78 p. s.i., these values increasing with throttle opening.

The Fig. 16 part section shows a modified accumulator casing 250 havingplunger 252 held upward against adjustable stop 256' by spring 255supported by retainer 267 which is lipped to act as a limit stop for thedownward motion of plunger 252. Adjacent smaller bore 268 is fitted withvalve 269 urgedl by spring 270 to close the cross port 271 connected tothe space above plunger 252' and to passage 257. The aperture 272 belowplunger 269 is open to inlet passage 254 and to the larger concentricbore 247 in which a check valve assembly is located.

The check valve assembly includes a shell 274 pierced at 275 and crimpedto grip plate 276v ported at 277 and disk valve 278 held on seat byspring 304 retained yinside the upper portion of shell 221.

When pressure is admitted from inlet passage 254 of Fig. 16, plunger 269is lifted against spring 270Hto expose port 272 and deliver pressure topassage 271, and to the head of piston 252' to compress spring 255.

Disc valve 278 is held closed by its spring 304.

This operation resembles that noted above for,V the delivery phase ofFig. 14 construction. The plunger 252y is progressively lowered againstspring 255 and the ref sistance being increased during this action, thenet effect is a gradual rise of modulator pressure passage 257, causingthe structure at the left of Fig. 14 to operate for increasing thepressure maintained by valve 125. During thisY phase, plunger 269Vremains above the opening of passage 271.

When valve of Fig. 15 is moved to .D. from the L position, the passage254 is connected to exhaust, and the disc valve 278 is impelled to openby the differential pressure between line 254 and 257, providing a quickrelief, augmented by the force of spring255 under plunger 252' and theforce of spring 147 of Fig. 14.

If the valve 130 of Fig. 15 has moved from L to the R position, thepassage 2541s not connected to exhaust at 233, and the modulation actionis retained for holding the increased minimum line pressure at the samevalue it had under the L operation, which takes care of the need forhigher actuator force on the reverse servo band due to its torquerequirement.

It will be understood that the Fig. 16 construction is an alternative tothat of the right-hand portion of Fig. 14, and that it is similarlyconnected by the corresponding passages to the valve 130' of Fig. 15 andthe vacuum modulator device at the left of Fig. 14.

The two modulator controls operate in the same gen eral manner, and theuseful results obtained are the same, guaranteeing an increasedregulated pressure `for initiating Vand holding drive in low andreverse.

For operation of the construction shown in the drawings, the selectorlever 290' of Fig. V13 is set in neutral N, or in parking P position, sothe engine starter switch may be engaged. When the engine is running,and the output shaft 60 is stopped, the impeller I of Fig. 1 is rotatingat engine speed, and turbine O slowly turns sun gear 27 under a slightidling torque. The pump P driven from drum 4 quickly supplies the systemof Figs. 7 to 11 with oil pressure Whenever the engine begins to rotate.

Mevemem of 'lever 29o to drive position D fernen mal drive shifts the'valve 130 from the Fig; 7 Vto the lig. 9

assignee position, feeding regulated pressure to port 174 and passage184 from port 172, applying pressure in cylinder 49 against clutchpiston 44 to compress the stack of clutch plates 4045. This couplesvshaft 11, sun gear 27 and sun gear 35, locking the gear assembly forunitary rotation. The converter turbine O now coupled to the load,cornes to rest. Bands 50 and 55 are released.

Opening of the engine throttle advances the speed of the engine andimpeller I, developing a torque on the turbine O, and the vehicle moves,first slowly at maximum torque multiplication speed and progressivelywith rise of vehicle speed, at diminishing torque multiplication asdescribed above, until the converter turbine O is driven at approximatel-to-l ratio. This point may be taken at 30 to 60 miles per hour, but inthe example herewith is at approximately 50 M. P. H., for full throttle.

Closing of the throttle permits the car to coast, and theseparate-working space blades 117, 120 provide engine braking. Thevehicle brakes may be applied and the vehicle stopped, without any needto move the lever 29d to i since the idling of the engine reducesimpeller speed to a potential torque-delivery value below a creep torquevalue of any consequence.

For establishing reverse drive, the lever 290 is shifted to move valve136 from the Fig. 8 to the Fig. 10 position, -to the end of levertravel. Pump pressure may -ow from feed port 172 to port 171 and line170 to reverse cylinder 65 to press piston 66 and bind band 55 on drum51. 1ncrease of engine speed lapplies torque to sun gear 27 and with thereaction effect of annulus gear 38 which is now stopped, shaft 66rotates reversely, -at a gear ratio in the present example of about 1.82to l, which is multiplied by the converter ratio, and varied towarddiminishing torque multiplication with rise of engine speed, providing avery effective reverse drive system.

Drive in low range may be obtained by moving lever to cause shift ofvalve from the Fig. 9 to the Fig. 8 position. For all ordinary trafficpurposes, this shift is not needed, but for emergency acceleration,maneuvering under poor traction conditions, multiplied engine braking onlong downhill grades, and 2nd gear climbing of steep hills, the lowrange is exceptionally useful; and additionally, the control apparatusfor easy shift between low range and reverse makes it possible to rock acar out of mud or gravel beds, snow or ice patches, and the like.

In .this Fig. 8 position the valve 130 directs the regulated pressurefrom port 172 to port 173 and line 187 for cylinder S5 lto actuate thepiston 84 to clamp band 50 on drum 37 and furnish torque reaction fromsun gear 35, in the disclosed example providing a low range reduction ofabout 1.82 to l, which is multiplied by the converter ratio as notedabove.

As outlined above, the actuating pressures for performing theseoperations are varied and rather exactly controlled by thepressure-regulator valve 125 of Figs. 6 to l1 which determines the neteffective pressure derived from the two pumps P and Q, as controlled bythe hydraulic pressures developed by the converter, by the variations inthe engine vacuum, and other variable controls. The net effect of theovercontrol on valve 125 in the Fig. 7 to ll arrangement is to developpressure response in accordance with throttle position, engine speed,vehicle torque and the torque demand, which control eects occur invarying proportions over the whole driving cycle, full throttle toidling, and under all variations of road conditions.

The Working oil supply is based on the sump of space S as a reservoir,located under the transmission casing portion 100C. The oil is drawnthru a screen and suction passages to the suction inlets 153 and 154 forboth pumps P and Q. Pump P is desirably of larger delivery capacity thanpump Q, and is able to ll the system rapidly as soon as the enginestarts, and to maintain full pressure for all low speed driverequirements. Over-supply is by-passed at 129 to the sump S or to thesuction passage 153, reducing friction losses. When a given car speed isreached, for example l5 to 18 M. P. H., the pump Q driven by shaft 60delivers suiiicient oil capacity and pressure to supply the wholesystem, its pressure operating the valve so as to relieve the pump P byholding open the relief passages therefor, further reducing the losses.The rear pump Q also serves to provide the required capacity andpressures, when the vehicle is towed to start a stalled engine.

The oil is circulated continuously thru the converter working spaces,maintaining them under a positive pressure at all times, assuringcooling circulation thru cooler 211, and gear lubrication circulationthru the passages connected to the lubrication line 212. Under heavyconverter loads the rise of converter outliow temperature causes thethermal valve 204 to increase flow through the cooler.

-In the understanding of the operation and actuation of the low rangeband 50 of Figs. l and 3, in starting from rest it should be observedthat in the gear train, with a forward rotation applied to sun gear 27,long planet 30 will endeavor to rotate reversely about its own center,short planet 31 will endeaver to rotate forwardly about its own center,and hence if there be a torque reaction developed by braking the drum 37of sun gear 35, drum must be restrained from rotating backward, that is,in Fig. 3 the drum 37 will try to rotate clockwise.

-Now if piston 84 apply load to band end 76, there will be aself-energizing tendency of band 50 following which the creation ofrising pressure on the piston S4 is wholly determined by the controlsutilized to regulate the actuator pressure.

For shift to L from N, the instant application of the low range bandcoupled with -the force applied by piston 84 assures that there will beno slip of the drum, and all slip incident to starting will be handledsolely by the torque converter.

'In downshifting from D to L, the drum 37 which had been rotatingforward at engine speed, is retarded to zero speed by band 50, which hasno self-energising action during this interval, therefore as the clutchplates 40-45 are relieved of their torque and drum 37 is retarded by theband 50, the transfer from direct coupling torque to reaction torque,under normal forward drive by the engine is accomplished by the uidpressure alone, stopping the band S0 gradually as the clutch plates areunloaded.

Under overrun downshift, such as in coasting down mountain grades, forlow range engine braking, there is no self-energised band action, asmooth shift action is accomplished by the character of the regulatedline pressure, used to engage and hold the band Sti. This is explainedabove in connection wi-th Figs. 14 to 16, as well as in the earlierdescription of the converter and vacuum controlled pressure modulation.

When the drum 37 comes to zero speed and the negative torque-reactioncomponent becomes sufficient to cause it to revolve backward, at theinstant it endeavors to do so, the self-wrapping action indicated byarrow X begins, and the self-locking force is added to that of the uidpressure. The band therefore has an initial phase when it isprogressively loaded by the fluid pressure while the drum is beingdecelerated by the gear torque coupling effect, and a second phase whenits torque reaction on the band generates a proportional self-wrappingforce augmenting that of the fluid pressure.

These effects Occur very quickly, and result in fast response to theopcrators ratio selection movement of the control lever 290 and valves130 or 13G', as described. This feature also makes the downshifttransition smooth, since while the capacity of clutch 40-45 is stillappreciable, there cannot be any self-wrapping action.

The operator may therefore lshift the ratio selector

